JP2904304B

PURPOSE:To quicken the leading of restoration of the operation from an unstable state into a stable state by varying the system of transmitting information from other control unit to one of control units in the stable and unstable states of the control units. CONSTITUTION:An EGI22 at the start of an engine receives a signal required for the control from a C/UA being other control unit. Then a period from a point of time (a) till a point of time (b) when a power supply voltage of the control unit restores a prescribed value is used as a start control period of the EGI 22 and the EGI 22 is in an unstable state when the control of the engine is difficult and the control of an engine torque is difficult especially, then the C/UA makes the data transmission to the EGI 22 periodic and decreases the period t1 more than a usual period t2. Thus, even when the power supply voltage of the control unit is lowered at the engine start, unstable communication is avoided.